PMID- 9503343
OWN - NLM
STAT- MEDLINE
DCOM- 19980429
LR  - 20240316
IS  - 0022-3751 (Print)
IS  - 1469-7793 (Electronic)
IS  - 0022-3751 (Linking)
VI  - 506 ( Pt 3)
IP  - Pt 3
DP  - 1998 Feb 1
TI  - Sensorimotor modulation of human cortical swallowing pathways.
PG  - 857-66
AB  - 1. Transcranial magnetic stimulation over motor areas of cerebral cortex in man 
      can activate short latency bilateral cortical projections to the pharynx and 
      oesophagus. In the present paper we investigate the interaction between pathways 
      from each hemisphere and explore how activity in these pathways is modulated by 
      afferent feedback from the face, pharynx and oesophagus. 2. Comparison of 
      unilateral and bilateral stimulation (using interstimulus intervals (ISIs) of 1, 
      5 or 10 ms between shocks) showed spatial summation of responses from each 
      hemisphere at an ISI of 1 ms, indicating that cortical efferents project onto a 
      shared population of target neurones. Such summation was not evident at ISIs of 5 
      or 10 ms. There was little evidence for transcallosal inhibition of responses 
      from each hemisphere, as described for limb muscles. 3. Single stimuli applied to 
      the vagus nerve in the neck or the supraorbital nerve, which alone produce 
      intermediate (onset 20-30 ms) and long (50-70 ms) latency reflex responses in the 
      pharynx and oesophagus, were used to condition the cortical responses. Compared 
      with rest, responses evoked by cortical stimulation were facilitated when they 
      were timed to coincide with the late part of the reflex. The onset latency was 
      reduced during both parts of the reflex response. No facilitation was observed 
      with subthreshold reflex stimuli. 4. Single electrical stimuli applied to the 
      pharynx or oesophagus had no effect on the response to cortical stimulation. 
      However, trains of stimuli at frequencies varying from 0.2 to 10 Hz decreased the 
      latency of the cortically evoked responses without consistently influencing their 
      amplitudes. The effect was site specific: pharyngeal stimulation shortened both 
      pharyngeal and oesophageal response latencies, whereas oesophageal stimulation 
      shortened only the oesophageal response latencies. 5. Cortical swallowing motor 
      pathways from each hemisphere interact and their excitability is modulated in a 
      site-specific manner by sensory input. The latter may produce a mixture of 
      excitation and inhibition at both brainstem and cortical levels.
FAU - Hamdy, S
AU  - Hamdy S
AD  - University of Manchester Gastroenterology Unit, Hope Hospital, London, UK.
FAU - Aziz, Q
AU  - Aziz Q
FAU - Rothwell, J C
AU  - Rothwell JC
FAU - Hobson, A
AU  - Hobson A
FAU - Thompson, D G
AU  - Thompson DG
LA  - eng
PT  - Clinical Trial
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - England
TA  - J Physiol
JT  - The Journal of physiology
JID - 0266262
SB  - IM
MH  - Adult
MH  - Cranial Nerves/physiology
MH  - Deglutition/*physiology
MH  - Electromagnetic Fields
MH  - Electromyography
MH  - Electrophysiology
MH  - Esophagus/innervation/physiology
MH  - Female
MH  - Functional Laterality
MH  - Humans
MH  - Male
MH  - Motor Cortex/*physiology
MH  - Neural Pathways/*physiology
MH  - Pharynx/innervation/physiology
PMC - PMC2230741
EDAT- 1998/03/21 00:00
MHDA- 1998/03/21 00:01
PMCR- 1999/02/01
CRDT- 1998/03/21 00:00
PHST- 1998/03/21 00:00 [pubmed]
PHST- 1998/03/21 00:01 [medline]
PHST- 1998/03/21 00:00 [entrez]
PHST- 1999/02/01 00:00 [pmc-release]
AID - 10.1111/j.1469-7793.1998.857bv.x [doi]
PST - ppublish
SO  - J Physiol. 1998 Feb 1;506 ( Pt 3)(Pt 3):857-66. doi: 
      10.1111/j.1469-7793.1998.857bv.x.